When I read old text I frequently note that this sort of typo seems more common in the 70s. There was likely nothing checking the spelling. And certainly no edi

When I read old text I frequently note that this sort of typo seems more common in the 70s. There was likely nothing checking the spelling. And certainly no editors putting squigglies. No place to Google your spelling doubts. And annoying to correct typewriter mistakes. Also, "undo" is a valid dictionary word.